Push-pull wheeled luggage with swingable rear wheels and at least one fixed front wheel

ABSTRACT

A wheeled luggage is configured to be pushed or pulled using a handle attached to the wheeled luggage. This “push-pull” wheeled luggage has a main luggage body with one or more swingable rear wheels at a rear edge of a lower portion of the main luggage body and one or more fixed front wheels in front of the one or more swingable rear wheels. Each front wheel has an elongated neck attached to a front lower portion of the main luggage body, which creates a backward tilt due to a higher ground clearance in the front lower portion. Each swingable rear wheel is configured to receive a directional force to steer the push-pull wheeled luggage. The backward tilt created by the elongated neck attached to the front lower portion of the main luggage body enables a user to push the push-pull wheeled luggage ergonomically by applying a forward-downward force to the handle.

BACKGROUND

This invention generally relates to luggage. In particular, theinvention relates to a novel wheeled luggage that reduces the user'sburden of lifting a portion of the wheeled luggage duringtransportation.

Wheeled luggage is a common method of carrying items for shippers andtravelers. One common type of wheeled luggage is a “pullman” case. Thereare several variations of pullman cases. One type of pullman cases hastwo fixed wheels located in the bottom-rear portion and a pair ofplastic legs in the bottom-front portion of the case. This type ofpullman case also has a handle or a strap located in the front portionof the case. A user is required to “pull” the case by lifting the frontportion of the case and pulling the case forward. The pullman case caneither have a solid or flexible casing. One disadvantage of the pullmancase is that the user has to lift the front portion of the case with ahandle and then pull the case forward, which requires a directlyproportional amount of pulling force relative to the weight of the case.Therefore, for pullman cases, increased weight of luggage requires aproportionally increased amount of pulling force from the user.

Another common type of pullman case has four wheels at the bottom of thecase. They are designed to be pulled like a wagon with a handle or astrap in the front portion of the case. In order to pull the caseergonomically, the handle or the strap of the four-wheeled pullman isdiagonally upward from the front portion of the case because a user istypically taller than the case. A Newtonian physics force diagram forthe required diagonally-upward force suggests that the user isessentially lifting a portion of the weight of the case (i.e. a verticalvector component from the diagonally upward vector representing the netforce). Therefore, heavier pullman cases assert substantial strain onthe user's arm during transportation. As a real-world example, thisdrawback is apparent to a user in with a heavy pullman-type luggage at alarge airport, where the user may be required to roll the luggage acrosshundreds or thousands of yards.

Therefore, a novel wheeled luggage which substantially reduces thestress on a user's arm is highly desirable.

SUMMARY

A push-pull wheeled luggage case is configured to be pushed and pulledby a user using a handle attached to the push-pull wheeled luggage case.The push-pull wheeled luggage case comprises a main luggage body with ahigher ground clearance in front relative to rear of the main luggagebody, wherein the main luggage body is configured to contain itemsinside, one or more swingable rear wheels located at a rear lowerportion of the main luggage body, wherein each swingable rear wheel isconfigured to change its direction based on a user's directional forceapplied to the handle attached to the luggage case, and one or morefixed front wheels located in front of the one or more swingable rearwheels, wherein an elongated neck for each fixed front wheel attached toa front lower portion of the main luggage body provides the higherground clearance relative to the one or more swingable rear wheels atthe rear lower portion of the main luggage body, thereby tilting themain luggage body backward when the one or more swingable rear wheelsand the one or more fixed front wheels are touching a flat surface.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a user pushing a push-pull wheeled luggage in accordancewith one or more embodiments of the invention.

FIG. 2 shows a user pulling a push-pull wheeled luggage in accordancewith one or more embodiments of the invention.

FIG. 3 shows a bottom portion of a push-pull wheeled luggage inaccordance with one or more embodiments of the invention.

FIG. 4 shows a bottom portion of a push-pull wheeled luggage inaccordance with one or more embodiments of the invention.

FIG. 5 shows a laid-down side view of a push-pull wheeled luggage inaccordance with one or more embodiments of the invention.

DETAILED DESCRIPTION

Specific embodiments of the invention will now be described in detailwith reference to the accompanying figures. Like elements in the variousfigures are denoted by like reference numerals for consistency.

In the following detailed description of embodiments of the invention,numerous specific details are set forth in order to provide a morethorough understanding of the invention. However, it will be apparent toone of ordinary skill in the art that the invention may be practicedwithout these specific details. In other instances, well-known featureshave not been described in detail to avoid unnecessarily complicatingthe description.

In general, embodiments of the invention relate to an apparatus forcarrying items in a luggage. More specifically, embodiments of theinvention relate to a wheeled luggage called a “push-pull” luggage whichcan be used for a “push mode” and a “pull mode” by the user using ahandle attached to the wheeled luggage.

Furthermore, embodiments of the invention enable the user to move thepush-pull wheeled luggage in a push mode with significantly less effortthan in a pull mode. More specifically, the invention alleviates theuser from lifting a portion of the weight of the push-pull wheeledluggage by tilting the luggage backward (i.e. towards the user) andincorporating one or more “swingable” rear wheels and one or morelonger-necked fixed front wheels attached to a lower portion of thepush-pull wheeled luggage.

In one embodiment of the invention, each swingable rear wheel isconfigured to rotate horizontally around a neck of the swingable rearwheel attached to a bottom portion of the push-pull wheeled luggage. Thetilting of the push-pull wheeled luggage is achieved by using anelongated neck for each fixed front wheel, thereby creating a higherfront ground clearance than a rear ground clearance provided by theswingable rear wheels.

FIG. 1 shows a user (111) pushing a push-pull wheeled luggage (103) withone or more swingable rear wheels (106) and one or more fixed frontwheels (113) in accordance with one embodiment of the invention. Thisactivity is defined as the “push mode.”

In one embodiment of the invention, the one or more fixed front wheels(113) provide a linear stability to movement of the push-pull wheeledluggage (103) and the one or more swingable rear wheels (106) provide adirectional and steering capability to the push-pull wheeled luggage(103) depending on the user's applied force on a handle (102) attachedto the push-pull wheeled luggage (103) via one or more support bars(101). It is important to note that the push-pull wheeled luggage (103)is tilted backward (i.e. towards the user (111)) because an elongatedneck (105) for each fixed front wheel (113) creates a higher frontground clearance than a rear ground clearance for the push-pull luggage(103). The elongated neck (105) typically contains an axis of wheelrotation to roll each fixed front wheel (113).

A circled area (6) shows an angle of contact by the one or more fixedfront wheels (113) to a flat surface. In one embodiment of theinvention, the one or more fixed front wheels (113) and correspondingelongated necks (105) form a perpendicular contact to the flat surface.In another embodiment of the invention, the one or more fixed frontwheels (113) and the corresponding elongated necks (105) form anon-perpendicular contact to the flat surface. In general, the angle ofcontact to the surface for the one or more fixed front wheels and thecorresponding elongated necks (105) do not inhibit the directional andsteering capability provided by the one or more rear swingable wheels(106).

Continuing with FIG. 1, the one or more rear swingable wheels (106) aretypically attached to one or more rear swingable necks (110). The one ormore rear swingable necks (110) are configured to horizontally andcircularly “sweep around” around one or more vertical axis to providethe directional and steering capability to the push-pull wheeled luggage(103). In the push-mode, the user can apply a force on the handle (102)to steer the push-pull wheeled luggage (103) to a desired direction. Thesteering input is reflected by orientation of the one or more rearswingable wheels (106) which “swing around” to a certain direction bythe attached one or more rear swingable necks (110).

In the push-mode, there is an engineering motivation for tilting thepush-pull wheeled luggage (103) backward (i.e. towards the user (111))in accordance with the invention. If the push-pull wheeled luggage (103)were not tilted backward and instead remained orthogonal to the flatsurface, it is ergonomically difficult to apply any horizontal forceF_(h1) (107) to the push-pull wheeled luggage (103) using the handle(102) without tipping the push-pull wheeled luggage (103). A simplevector component diagram of a net force provided by the user, F_(u1)(109), shows a clear advantage of tilting the push-pull wheeled luggage(103) backward when the user decides to apply a diagonalforward-downward force, F_(u1) (109), to the handle. A simple Newtonianphysics vertical and horizontal vector analysis shows that a horizontalvector, F_(h1) (107), provides a forward directional push to thepush-pull wheeled luggage (103). A vertical vector, F_(v1) (108), on theother hand, provides a downward force to the one or more swingable rearwheels (106) and the one or more fixed front wheels (113), therebyhelping stability of the push-pull wheeled luggage (103) when the user(111) applies F_(u1) (109).

An inherent advantage of the present invention comes from the push modeof the push-pull wheeled luggage (103). Unlike a pull mode, in which theuser is forced to lift a portion of the weight of the push-pull wheeledluggage, the push mode benefits from an inherent advantage in laws ofphysics. By applying the diagonal forward-downward force (i.e. pushmode) instead of a forward-upward force (i.e. pull mode), the userleverages gravity and does not have to lift a portion of the weight ofthe push-pull wheeled luggage. Over long distances, this force advantageresults in superior usability and efficiency for movement of thepush-pull wheeled luggage. Ease of movement of the push-pull wheeledluggage during the push mode is a key feature of the invention.

FIG. 2 shows a user (211) lifting one or more fixed front wheels (206)from a surface and pulling a push-pull wheeled luggage (203) using oneor more swingable rear wheels (210) by applying a forward-upward force,F_(u2) (209), in accordance with the invention. This activity is definedas the “pull mode”.

In one embodiment of the invention, the one or more swingable rearwheels (210) provide a directional and steering capability to themovement of the push-pull wheeled luggage (203). Unlike the push mode,the pull mode requires the user (211) to apply the forward-upward force,F_(u2) (209), to a handle (202) attached to the push-pull wheeledluggage via one or more support bars (201). Applying the forward-upwardforce, F_(u2) (209), necessitates the user (211) to lift a portion ofthe weight of the push-pull wheeled luggage (203).

A simple Newtonian physics vector diagram (207, 208, 209) demonstratesthis added burden to the user (211) for the pull mode. The net forceapplied by the user (211) is illustrated by a vector, F_(u2) (209),which can be broken down into components, a horizontal vector, F_(h2)(207), and a vertical vector, F_(v2) (208). The horizontal vector,F_(h2) (207) is responsible for pulling the push-pull wheeled luggage(203) forward. The vertical vector, F_(v2) (208), essentially requiresthe user (211) to lift up a portion of the weight of the push-pullwheeled luggage (203). In essence, lifting up the portion of the weightof the push-pull wheeled luggage (203) is inefficient and unnecessary(i.e. in light of the push mode described for FIG. 1), but it is aninherent force required in the pull mode.

Continuing with FIG. 2, although the pull mode requires more effort tothe user (211), it is a conventional mode of moving wheeled luggages.The push-pull wheeled luggage (203) in accordance with the inventionprovides this additional mode of operation for further user convenience.A Newtonian physics-based force efficiency provided by the novel pushmode as described in FIG. 1 and the flexibility of the conventional pullmode as described in FIG. 2 give the present invention great utility andconvenience to the user (211).

FIG. 3 shows a bottom surface of a push-pull wheeled luggage (303) inaccordance with one or more embodiments of the invention. In thisparticular embodiment, a pair of swingable rear wheels (304) provides adirectional and steering capability to the push-pull wheeled luggage(303) for both push and pull modes as described in FIG. 1 and FIG. 2. Afixed front wheel (301) is located in front of the pair of swingablerear wheels (304). In one or more embodiments of the invention, thefixed front wheel (301) is roughly equidistant from each swingable rearwheel (304) and forms a geometrical configuration similar to a tricycle.

Continuing with FIG. 3, the term “swingable” defines the horizontalcircular movement of the pair of swingable rear wheels (304), as shownby arrows (302). The pair of swingable rear wheels (304) can be attachedto a rear portion of the push-pull wheeled luggage (303) by riveting,drilling, or bolting swingable necks (306) into the bottom surface ofthe push-pull wheeled luggage (303). Similarly, the fixed front wheel(301) can be attached to a front portion of the push-pull wheeledluggage (303) by riveting, drilling, or bolting an elongated neck (305)into the bottom surface of the push-pull wheeled luggage (303). Thistricycle-like configuration on the bottom surface of the push-pullwheeled luggage (303) is a preferred embodiment of the invention.

FIG. 4 shows a bottom surface of a push-pull wheeled luggage (403) inaccordance with one or more embodiments of the invention. In thisparticular embodiment, a pair of swingable rear wheels (404) provides adirectional and steering capability to the push-pull wheeled luggage(403) for both push and pull modes as described in FIG. 1 and FIG. 2. Apair of fixed front wheels (405) is located in front of the pair ofswingable rear wheels (404). In one or more embodiments of theinvention, this four-wheel configuration is optimal for supporting aheavier weight of the push-pull wheeled luggage (403) compared to thetricycle-like configuration of the push-pull wheeled luggage (303)described in FIG. 3.

Continuing with FIG. 4, the term “swingable” defines the horizontalcircular movements of the pair of swingable rear wheels (404), as shownby arrows (402). The pair of swingable rear wheels (404) can be attachedto a rear portion of the bottom surface of the push-pull wheeled luggage(403) by riveting drilling, or bolting swingable necks (401) into thebottom surface of the push-pull wheeled luggage (403). Similarly, thepair of fixed front wheels (405) can be attached to a front portion ofthe bottom surface of the push-pull wheeled luggage (403) by riveting,drilling, or bolting elongated necks (406) into the bottom surface ofthe push-pull wheeled luggage (403).

FIG. 5 shows a laid-down view of a push-pull wheeled luggage (501) inaccordance with one or more embodiments of the invention. In thisparticular embodiment, a support bar (504) typically houses aretractable handle (505), from which a user exerts pushing or pullingforce to the push-pull wheeled luggage (501). The support bar (504) andthe retractable handle (505) are typically made of metal or plastic. Inone embodiment, one or more swingable rear wheels (507) can be heldtogether by one or more swingable necks (506) which are typicallyriveted, drilled, or bolted on to a lower rear portion of the push-pullwheeled luggage (501). Similarly, one or more fixed front wheels (502)can be held together by one or more elongated necks (503), which aretypically riveted, drilled, or bolted on to a lower front portion of thewheeled luggage (501).

While the invention has been described with respect to a limited numberof embodiments, those skilled in the art, having benefit of thisdisclosure, will appreciate that other embodiments can be devised whichdo not depart from the scope of the invention as disclosed herein.Accordingly, the scope of the invention should be limited only by theattached claims.

1. A push-pull wheeled luggage case configured to be pushed and pulledby a user using a handle attached to the push-pull wheeled luggage case,the push-pull wheeled luggage case comprising: a main luggage body witha higher ground clearance in front relative to rear of the main luggagebody, wherein the main luggage body is configured to contain itemsinside; a pair of swingable rear wheels located at a rear lower portionof the main luggage body, wherein each swingable rear wheel isconfigured to rotate around a vertical axis for a horizontally circularswinging motion based on a directional force applied by the user; afixed front wheel located in front of the pair of swingable rear wheels,wherein an elongated neck of the fixed front wheel attached to a frontlower portion of the main luggage body provides the higher groundclearance in the front relative to the rear of the main luggage body,thereby tilting the main luggage body backward when the pair ofswingable rear wheels and the fixed wheel are touching a flat surface.2. The push-pull wheeled luggage case of claim 1, wherein tilting themain luggage body backward means that the main luggage body is tiltedtowards the user standing behind the push-pull wheeled luggage case. 3.The push-pull wheeled luggage case of claim 1, wherein the vertical axisfor the horizontally circular swinging motion for each swingable rearwheel is provided by a swingable neck attached to the rear lower portionof the main luggage body.
 4. The push-pull wheeled luggage case of claim1, wherein each swingable rear wheel of the pair of swingable rearwheels is located at each corner of the rear lower portion of the mainluggage body.
 5. The push-pull wheeled luggage case of claim 1, whereinthe pair of swingable rear wheels enables the user to push the push-pullwheeled luggage case to a desired direction by applying a diagonalforward-downward force on the handle of the push-pull wheeled luggagecase and wherein the fixed front wheel located in front of the swingablerear wheels provides a straight-line stability.
 6. The push-pull wheeledluggage case of claim 2, wherein the push-pull wheeled luggage case canbe pulled by the user by further tilting the main luggage body towardsthe user, thereby detaching the fixed front wheel from the flat surfaceand relying only on the pair of swingable rear wheels for pullingmovement of the push-pull wheeled luggage case.
 7. A push-pull wheeledluggage case configured to be pushed and pulled by a user using a handleattached to the push-pull wheeled luggage case, the push-pull wheeledluggage case comprising: a main luggage body with a higher groundclearance in front relative to rear of the main luggage body, whereinthe main luggage body is configured to contain items inside; one or moreswingable rear wheels located at a rear lower portion of the mainluggage body, wherein each swingable rear wheel is configured to changeits direction based on a user's directional force applied to the handleattached to the luggage case; and one or more fixed front wheels locatedin front of the one or more swingable rear wheels, wherein an elongatedneck for each fixed front wheel attached to a front lower portion of themain luggage body provides the higher ground clearance relative to theone or more swingable rear wheels at the rear lower portion of the mainluggage body, thereby tilting the main luggage body backward when theone or more swingable rear wheels and the one or more fixed front wheelsare touching a flat surface.
 8. The push-pull wheeled luggage case ofclaim 7, wherein tilting the main luggage body backward means that themain luggage body is tilted towards the user standing behind thepush-pull wheeled luggage case.
 9. The push-pull wheeled luggage case ofclaim 7, wherein the one or more swingable rear wheels are located nearat least one corner of the rear lower portion of the main luggage body.10. The push-pull wheeled luggage case of claim 7, wherein the one ormore swingable rear wheels enable the user to push the push-pull wheeledluggage case to a desired direction by applying a diagonalforward-downward force on the handle of the push-pull wheeled luggagecase and wherein the one or more fixed front wheels located in front ofthe swingable rear wheels provide a straight-line stability.
 11. Thepush-pull wheeled luggage case of claim 8, wherein the push-pull wheeledluggage case can be pulled by the user by further tilting the mainluggage body towards the user, thereby detaching the one or more fixedfront wheels from the flat surface and relying only on the one or moreswingable rear wheels for pulling movement of the push-pull wheeledluggage case.
 12. A push-pull wheeled luggage case configured to bepushed and pulled by a user using a handle attached to the push-pullwheeled luggage case, the push-pull wheeled luggage case comprising: amain luggage body with a higher ground clearance in front relative torear of the main luggage body, wherein the main luggage body isconfigured to contain items inside; one or more swingable rear wheelslocated at a rear lower portion of the main luggage body, wherein eachswingable rear wheel is configured to change its direction based on auser's directional force applied to the handle attached to the luggagecase; a plurality of fixed front wheels located in front of the one ormore swingable rear wheels, wherein an axle going through the pluralityof fixed front wheels provides a common axis of rotation for theplurality of fixed front wheels; one or more elongated necks attached tothe plurality of fixed front wheels and a front lower portion of themain luggage body, wherein the one or more elongated necks for theplurality of fixed front wheels provide a higher ground clearancerelative to the one or more swingable rear wheels at the rear lowerportion of the main luggage body, thereby tilting the main luggage bodybackward when the one or more swingable rear wheels and the plurality offixed front wheels are touching a flat surface.
 13. The push-pullwheeled luggage case of claim 12, wherein tilting the main luggage bodybackward means that the main luggage body is tilted towards the userstanding behind the push-pull wheeled luggage case.
 14. The push-pullwheeled luggage case of claim 12, wherein the one or more swingable rearwheels are located near at least one corner of the rear lower portion ofthe main luggage body.
 15. The push-pull wheeled luggage case of claim12, wherein the one or more swingable rear wheels enable the user topush the push-pull wheeled luggage case to a desired direction byapplying a diagonal forward-downward force on the handle of thepush-pull wheeled luggage case and wherein the plurality of fixed frontwheels located in front of the swingable rear wheels provide astraight-line stability.
 16. The push-pull wheeled luggage case of claim13, wherein the push-pull wheeled luggage case can be pulled by the userby further tilting the main luggage body towards the user, therebydetaching the plurality of fixed front wheels from the flat surface andrelying only on the one or more swingable rear wheels for pullingmovement of the push-pull wheeled luggage case.